The present invention pertains to an apparatus and method for bonding a sheet material to an elongated base material, and its application to the manufacture of flexible flat cables.
An apparatus for manufacturing a flexible flat cable or an electric tape cable, as depicted in FIG. 1, is one of the known apparatuses of the type that are used to bond a sheet material to an elongated base material. In the flat cable-manufacturing apparatus as shown, a plurality of flat rectangular electric conductors 100, arranged parallel to one another in an elongated manner, are continuously transferred on rolls and caused to run between a pair of hot rolls 101. Two insulating tape sheets 102 are also guided by guide rolls 103 to be placed on top of and underneath the conductors 100 and are bonded thereto by the hot rolls 101 to provide a flexible flat cable blank 104. In order to provide lead openings for the conductors 100 while leaving connecting portions 102a necessary for the continuous transport of the sheet, rectangular holes 105 as shown in FIG. 2 are formed in each insulating tape sheet 102 by a respective press machine 106 prior to the bonding step, and, following the bonding step, widthwise margins of the resulting flexible flat cable blank 104, indicated by two-dot and dash lines X in FIG. 3, are cut by a slitting device (not shown) to remove the aforesaid connecting portions, i.e., the portions indicated by the numeral 102a, as well as the marginal portions 102b which are in excess of the predetermined width of a finished flexible flat cable.
In the aforesaid known apparatus, however, the debris of the insulating tape sheets 102 produced by forming the holes 104 as well as their connecting and marginal portions 102a and 102b to be removed are wasteful and lead to an increased cost for raw materials. In addition, when the size of the rectangular holes 105 must be changed to manufacture flexible flat cables of different sizes, the resetting of the press machines is required, resulting in diminished productivity. Furthermore, the noise of the press machines in operation is unduly great.
A possible solution to the problems posed, is to cut discrete tapes from each insulating tape strip traveling on the hot rolls 101, prior to the subsequent bonding step. However, once the insulating tape strips are cut into discrete tapes, they tend to easily fall from the hot rolls 101 before they reach the position where they are bonded to the conductors 100.